Run Method every 5 seconds without creating new eventhandlers

Question

I need to run a method every 5 seconds in a c# console program (this program opens a Win form UI in a separate thread).

Every attempt I have had at creating timer has failed due to the eventhandler not being killed off after each time the _timer.Elapsed (or _timer.Tick) reaches 0.

This is resulting in multiple calls to my method, and subsequently the information I'm collection gets duplicated (3 times for each eventhandler).

Does anyone have an example of a way I can call my method every 5 seconds, that wont result in this duplication?

   public static System.Timers.Timer _timer = new System.Timers.Timer();


    static void Main(string[] args)
    {
        //Check Registry for existing Robo config
        RegistryTasks StartupRegistryCheck = new RegistryTasks();
        StartupRegistryCheck.StartupRegistryCheck();

        RetrieveJobs();

        _timer.Interval = 5000;
        _timer.Elapsed += OnTimedEvent;
        _timer.Enabled = true;

        new Thread(() =>
        {
            //Thread.Sleep(6000);
            load_UI();
        }).Start();
    }

    static void RetrieveJobs()
    {
        RegistryTasks getIPs = new RegistryTasks();
        getIPs.GetIPFromRegistry(Servers);
        //Console.WriteLine(Servers);
        foreach (object o in Servers)
        {
            dynamic expObj = new ExpandoObject();
            expObj = o;
            string IP = expObj.serverObjectIp;
            int Port = expObj.serverObjectPort;

            // Start synchronous socket connections
            string JobList = SocketClient.GetJobList(IP, Port);

            // Uncomment the lines below to use async sockets (currently not working)
            // IPHostEntry ipHostInfo = Dns.GetHostEntry(IP);
            // IPAddress ipAddress = ipHostInfo.AddressList[0];
            // IPEndPoint ipe = new IPEndPoint(ipAddress, Port);
            // Socket s = new Socket(AddressFamily.InterNetwork,
            // SocketType.Stream, ProtocolType.Tcp);
            // string JobList = ClientSocketAsync.Connect(ipe, s);

            // Split Retrieved JobLiST XML data into Arrays for later use.
            XmlSplitter.splitXml(JobList, out ActiveJobsArray, out CompletedJobsArray, out PendingJobsArray);
        }
    }

    public static void OnTimedEvent(object source, System.Timers.ElapsedEventArgs e)
    {
        _timer.Stop();
        RetrieveJobs();
        _timer.Start();
    }

The code in question is above :(

Current output... below.

Timer hit 0.
Received data 1
Received data 2
Received data 3
Timer hit 0.
Received data 1
Received data 2
Received data 3
Received data 1
Received data 2
Received data 3
Timer hit 0.
Received data 1
Received data 2
Received data 3
Received data 1
Received data 2
Received data 3
Received data 1
Received data 2
Received data 3

Update... So I still haven't figured out why my timer wont work without duplicating itself. Main is only called once. there are no other references to a timer in any other classes. The only reference or hint of a timer is found in the code previously mentioned.

So, as an experiment to see if it is cured in a new program, I created a new console application.

I added a timer, and a "MessageBox.Show()" to block the program and prevent an exit. 100% of the code written for this test can be found below, strangely, the program exits immediately, and no MessageBox is displayed. The timer doesn't even perform one loop (as it would be expected to with AutoReset set to false).

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ConsoleApplication1
{
    class Program
    {
        public static System.Timers.Timer _timer = new System.Timers.Timer();

    static void Main(string[] args)
    {
        _timer.AutoReset = false;
        _timer.Interval = 5000;
        _timer.Elapsed += OnTimedEvent;
        _timer.Enabled = true;
        _timer.Start();
    }

    static void OnTimedEvent(object source, System.Timers.ElapsedEventArgs e)
    {
        _timer.Stop();
        Console.WriteLine("Timer Stopped");
        //_timer.Elapsed -= OnTimedEvent;
        RetrieveJobs();
        _timer.Start();
        Console.WriteLine("Timer Started");
    }

    static void RetrieveJobs()
    {
        Console.WriteLine("Timer hit 0");
        MessageBox.Show("Blocking Timer Program Exit for Timer to run!");
    }
    }
}

This is now resolved. Please close.

Turns out my Servers object in the RetrieveJobs() foreach loop is getting duplicated. Instead of listing 3 servers, its collection those same 3 servers from the registry and adding them to the object. My own fault for not spotting this sooner. Thanks to all who offered help though :).